It's not just cross play, Sony has been very happy to take advantage of their market leader status this gen.
They didn't allow EA access on PS4, they didn't allow mods on PS4, they don't allow cross play with other consoles, they don't have any BC (the only Playstation not to have it), it doesn't have refunds, they still can't change PSN IDs, they've shut down studios without replacing them with new one's, They put out PSVR with very little support, they didn't want to spend the extra $20 to put a 4k blu ray in the Pro, there's a laundry list of things they could do better, many of these problems are not technical issues, its just them taking advantage of the fact that they're the market leader and they can get away with it.
But as the OP mentioned, the first party devs are just killing it lately so alot of people are willing to put up with it....like me.
"what spurred this influx of threads recently". half of what you listed is age old stuff, not that that should give them a free pass to skip on whatever customers want, its just weird to see it rehashed so often recently. "they are market leader and can get away with it" also comes across more like agenda driven than an assessment based on substantial evidence.
BC was gonna be a hard task due to different architecture, i'm not the most savvy in these matters but i've been told such and seen it discussed in this very same forum. even so, the PS4 not having native BC is information available to potential customers. How you buy something and get mad it doesn't do something years down the line all because the competition started to do it? still, PS Now exists as some sort of weird way of bridging some of that gap, but from what i see on Era, people would want it to be free. Maybe they should offer a discounted version of the service for Plus subscribers (i don't know if they do already) because i don't think running the service or the infrastructure necessary for the service is cost free for them.
refunds aren't an universal thing, but based on your location, and the reps you speak to, you can certainly get refunds from sony. not ideal, and they certainly should improve in this regard.
i remember reports about there being technical limitations that prevented them from simply enabling PSN ID changes, but they did say they are working on it no? (time frame expected was within a year, and that was at PS experience in december last year)
studios get shut down all the time. it is a business. studios don't just stay open if they are not successful just so people don't use it as a bullet point in these weird gaming forum lists. and WWS in general and their first party offerings have been pretty good according to this thread...so like?
I dunno much about PSVR and its support, and the PRO not having a 4K blu ray player seems like non issues to me and easily avoidable for anyone else. don't buy them products if they do not meet your demands/specifications. how are people using the Pro not having a 4K player as potential evidence of "arrogant sony" or "sony is only doing this because they are market leader" thing? they went with choices that were certainly pondered against factors like cost, production, pricing, demand, availability etc
i dunno man.